Petroleum shipments by rail have fallen since last summer as plummeting crude prices have caused the biggest slowdown of oil drilling on record. BNSF Railway shut its mainline near the town of Galena, Illinois, from March 5-9 after a derailment, causing delays and reroutings.

The reason for the go-slow approach is wariness among lawmakers that they’d be blamed if gasoline prices climb after the ban is lifted. And the oil industry itself is split, with some refiners, who benefit from low prices, opposed to lifting the ban.

The widening discount of US oil is proving a boon to the economy, with the average household forecast to save $750 in gasoline costs this year, according to the EIA. It will also boost profit margins for US refiners, who have access to cheaper feedstock costs.

The EIA pegged crude storage capacity at refineries and tank farms in the US at 521 million bbl at the end of September. With inventories rising 8.4 million bbl last week to a record 434 million, it may appear at first glance like supplies from the shale boom are on a collision course with tank tops.